Chemosynthesis Definition and Examples

Chemosynthesis Definition and Examples Chemosynthesis is the conversion of carbon compounds and other molecules into organic compounds. In this biochemical reaction, methane or an inorganic compound, such as hydrogen sulfide or hydrogen gas, is oxidized to act as the energy source. In contrast, the energy source for photosynthesis (the set of reactions through which carbon dioxide and water are converted into glucose and oxygen) uses energy from sunlight to power the process. The idea that microorganisms could live on inorganic compounds was proposed by Sergei Nikolaevich Vinogradnsii (Winogradsky) in 1890, based on research conducted on bacteria which appeared to live from nitrogen, iron, or sulfur. The hypothesis was validated in 1977 when the deep sea submersible Alvin observed tube worms and other life surrounding hydrothermal vents at the Galapagos Rift. Harvard student Colleen Cavanaugh proposed and later confirmed the tube worms survived because of their relationship with chemosynthetic bacteria. The official discovery of chemosynthesis is credited to Cavanaugh. Organisms that obtain energy by oxidation of electron donors are called chemotrophs. If the molecules are organic, the organisms are called chemoorganotrophs. If the molecules are inorganic, the organisms are terms chemolithotrophs. In contrast, organisms that use solar energy are called phototrophs. Chemoautotrophs and Chemoheterotrophs Chemoautotrophs obtain their energy from chemical reactions and synthesize organic compounds from carbon dioxide. The energy source for chemosynthesis may be elemental sulfur, hydrogen sulfide, molecular hydrogen, ammonia, manganese,  or iron. Examples of chemoautotrophs include bacteria and methanogenic archaea living in deep sea vents. The word chemosynthesis was originally coined by Wilhelm Pfeffer in 1897 to describe energy production by oxidation of inorganic molecules by autotrophs (chemolithoautotrophy). Under the modern definition, chemosynthesis also describes energy production via chemoorganoautotrophy. Chemoheterotrophs cannot fix carbon to form organic compounds. Instead, they can use inorganic energy sources, such as sulfur (chemolithoheterotrophs) or organic energy sources, such as proteins, carbohydrates, and lipids (chemoorganoheterotrophs). Where Does Chemosynthesis Occur? Chemosynthesis has been detected in hydrothermal vents, isolated caves, methane clathrates, whale falls, and cold seeps. It has been hypothesized the process may permit life below the surface of Mars and Jupiters moon Europa. as well as other places in the solar system. Chemosynthesis can occur in the presences of oxygen, but it is not required. Example of Chemosynthesis In addition to bacterial and archaea,  some larger organisms rely on chemosynthesis. A good example is the giant tube worm which is found in great numbers  surrounding deep hydrothermal vents. Each worm houses chemosynthetic bacteria in an organ called a trophosome. The bacteria oxidize sulfur from the worms environment to produce the nourishment the animal needs. Using hydrogen sulfide as the energy source, the reaction for chemosynthesis is: 12 H2S 6 CO2 → C6H12O6 6 H2O 12 S This is much like the reaction to produce carbohydrate via photosynthesis, except photosynthesis releases oxygen gas, while chemosynthesis yields solid sulfur. The yellow sulfur granules are visible in the cytoplasm of bacteria that perform the reaction. Another example of chemosynthesis was discovered in 2013 when bacteria were found living in basalt below the sediment of the ocean floor. These bacteria were not associated with a hydrothermal vent. It has been suggested the bacteria use hydrogen from the reduction of minerals in seawater bathing the rock. The bacteria could react hydrogen and carbon dioxide to produce methane. Chemosynthesis in Molecular Nanotechnology While the term chemosynthesis is most often applied to biological systems, it can be used more generally to describe any form of chemical synthesis brought about by random thermal motion of reactants. In contrast, mechanical manipulation of molecules to control their reaction is called mechanosynthesis. Both chemosynthesis and mechanosynthesis have the potential to construct complex compounds, including new molecules and organic molecules. Resources and Further Reading Campbell, Neil A., et al. Biology. 8th ed., Pearson, 2008.Kelly, Donovan P., and Ann P. Wood. â€Å"The Chemolithotrophic Prokaryotes.† The Prokaryotes, edited by Martin Dworkin, et al., 2006, pp. 441-456.Schlegel, H.G. â€Å"Mechanisms of Chemo-Autotrophy.† Marine Ecology: a Comprehensive, Integrated Treatise on Life in Oceans and Coastal Waters, edited by Otto Kinne, Wiley, 1975, pp. 9-60.Somero, Gn. â€Å"Symbiotic Exploitation of Hydrogen Sulfide.† Physiology, vol. 2, no. 1, 1987, pp. 3-6.

Microsoft Certified Professional (MCP) Training

Microsoft Certified Professional (MCP) Training The Microsoft Certified Professional (MCP) credential is usually the first Microsoft title earned by certification seekers– but it’s not for everybody. Here’s what you need to know: MCP Is the Easiest Microsoft Credential to Obtain The MCP title only requires passing a single test, normally an operating system test like Windows XP or Windows Vista. That means it takes the least amount of time and money to get.That does not mean, however, that it’s a breeze. Microsoft tests a lot of knowledge, and it will be difficult to pass the exam without some time in a helpdesk or network environment. The MCP Is for Those Who Want to Work on Windows Networks There are other Microsoft certifications for those who want to work in other areas of IT: for example, databases (Microsoft Certified Database Administrator – MCDBA), software development (Microsoft Certified Solutions Developer – MCSD) or high-level infrastructure design (Microsoft Certified Architect – MCA).If your goal is to work with Windows servers, Windows-based PCs, end users and other aspects of a Windows network, this is the place to start. Gateway to Higher-Level Certifications The MCP is often the first stop on the road to the Microsoft Certified Systems Administrator (MCSA) or Microsoft Certified Systems Engineer (MCSE) credentials. But it does not have to be. Plenty of folks are happy to get the single certification and have no need, or desire, to move up. But the upgrade path to the MCSA and MCSE is easy, since the test you have to pass will count toward the other titles.Since the MCSA requires passing four tests, and the MCSE takes seven, getting the MCP will a) Get you that much closer to your goal and b) Help you decide if this type of certification, and career, is for you. It Leads Most Often to an Entry-Level Job Hiring managers often look for MCPs to work on a corporate helpdesk. MCPs also find jobs in call centers, or as first-tier support technicians. In other words, it’s a foot in the door to a good IT career. Don’t expect IBM to hire you as a system administrator after waving your MCP paper in someone’s face.Especially in a tough economy, IT jobs can be scarce. But having a Microsoft certification on your resume can help give you an edge over non-certified candidates. A prospective employer knows you have a base level of knowledge, and the drive to gain knowledge of your prospective, or current, field. The Average Pay Is High According to the latest salary survey by respected website mcpmag.com, an MCP can expect a salary of around $70,000. That’s not bad at all for a single-test certification.Keep in mind that those figures take many factors into account, including years of experience, geographic location and other certifications. If you’re a career-changer and getting your first job in IT, your salary will quite likely be substantially less than that.Consider all these factors when deciding whether or not to go for the MCP title. MCPs are well-respected in IT shops, and have skills that can help them on their way to lucrative, satisfying careers.